JP2014143634A - Communication apparatus, method for controlling communication apparatus, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently control the respective roles of communication apparatuses in a service executed between them and the respective roles of them in a layer different from the layer of the service.SOLUTION: A communication apparatus determines whether to operate as a base station or as a terminal. The communication apparatus determines to operate as a base station if the apparatus functions as a server of a service executed between the apparatus and another communication apparatus.

Description

  The present invention relates to a communication device, a communication device control method, and a program.

  In recent years, there is an increasing number of cases where a wireless LAN station function is installed in an electronic device such as a digital camera or a printer, and the electronic device is used as a communication device connected to a wireless LAN. For example, Patent Document 1 discloses a method for facilitating image sharing by mounting a wireless LAN function in a digital camera.

  In addition, a standard called Wi-Fi Direct (registered trademark) has been established by Wi-Fi Alliance. In Wi-Fi Direct (hereinafter, WFD), a protocol for determining whether each electronic device operates as a wireless LAN access point or a wireless LAN station is defined. By executing the protocol, it is possible to automatically determine which of the electronic devices is a wireless LAN access point and which is a wireless LAN station. By using the WED, there is no need to prepare an access point separately, and various services (image sharing, printing, etc.) can be performed by directly communicating with each other, improving user convenience. .

  In addition, a function (service discovery function) for searching for the contents of services provided by other devices in the application layer is defined as an optional function of Wi-Fi Direct. According to this service discovery function, it is possible to know information on services provided by an electronic device that is a connection partner before executing the connection process, and the convenience for the user is improved.

JP 2011-35768 A

  In the above prior art, connection control in the radio layer using WFD and service control in the application layer, which is a higher layer than the radio layer, are independent. For this reason, there is a possibility that a role of the wireless layer that is not suitable for service execution in the application layer is set.

  Further, every time the role in the service in the application layer is changed, reconnection of the wireless layer each time increases the processing load and is inefficient.

  Accordingly, an object of the present invention is to provide a communication device that efficiently controls the role of each communication device in a service executed between the communication devices and the role of each communication device in a layer different from the layer of the service. And

  In order to achieve the above object, the communication device of the present invention operates as a base station, constructs a network, operates as a terminal, participates in a network, and operates as the base station. A determination unit that determines whether to operate as the terminal; a transmission unit that operates as a client of a service executed between the other communication devices and transmits a file to the other communication device; and another communication device Receiving means for receiving a file transmitted from the other communication device, and the determining means is executed with the other communication device. When operating as a service server, it is determined to operate as the base station.

  In order to achieve the above object, the communication apparatus of the present invention includes a construction unit that operates as a base station to construct a network, a participation unit that operates as a terminal and participates in the network, the base station, and the terminal. Determined by the determining unit, a communication unit that communicates with another communication device, a determining unit that determines a role of the communication device for executing a service in an application layer, and And changing means for changing the role determined by the determining means in a state where the role for communication by the communication means is maintained after executing the service in the application layer according to the role.

  ADVANTAGE OF THE INVENTION According to this invention, the role of each communication apparatus in the service performed between communication apparatuses and the role of each communication apparatus in a layer different from the layer of the said service can be controlled efficiently.

Block diagram of the device Software function block diagram in the device The figure which shows an example of the network configuration to which this invention is applied Operation sequence diagram in Embodiment 1 Operation flow diagram of apparatus in embodiment 1

[Example 1]
Hereinafter, the communication apparatus according to the present embodiment will be described in detail with reference to the drawings. In the following, an example using a wireless LAN system compliant with the IEEE 802.11 series will be described, but the communication form is not necessarily limited to the wireless LAN compliant with IEEE 802.11.

  A hardware configuration in a case suitable for the present embodiment will be described.

  FIG. 1 is a block diagram showing an example of the configuration of each device described below according to an embodiment to which the present invention can be applied. Reference numeral 101 denotes the entire apparatus. A control unit 102 controls the entire apparatus by executing a control program stored in the storage unit 103. The control unit 102 includes one or more processors such as a CPU and an MPU. The control unit 102 also performs communication parameter setting control with other devices. A storage unit 103 stores a control program executed by the control unit 102 and various types of information such as communication parameters. Further, the storage unit 103 may store image data, files, and the like generated by the communication device or received from the external device. The storage unit 103 includes various memories such as a ROM, a RAM, an HDD, and a flash memory. Various operations to be described later are performed by the control unit 102 executing a control program stored in the storage unit 103.

  A wireless unit 104 performs wireless LAN communication conforming to the IEEE802.11 series. Reference numeral 105 denotes a display unit that performs various displays, and has a function capable of outputting visually recognizable information such as an LCD or LED, or outputting sound such as a speaker. The display unit 105 has a function of outputting at least one of visual information and sound information.

  Reference numeral 107 denotes an antenna control unit, and reference numeral 108 denotes an antenna. The antenna 108 is controlled to transmit and receive signals by wireless communication. An operation unit 109 is used by the user to perform various inputs and operate the communication apparatus. The operation unit 109 includes various buttons, a touch panel, and the like.

  The service providing unit 110 has a function of providing an application layer service included in the communication device. For example, when the communication device is a printer, a printing function is provided, and when the communication device is a digital camera, an imaging function is provided.

  FIG. 1 is an example, and the communication apparatus 101 may have a hardware configuration other than the hardware configuration shown in FIG.

  FIG. 2 is a block diagram illustrating an example of a configuration of software function blocks that execute a communication control function described later. Reference numeral 201 denotes an entire software function block. A Discovery control unit 202 operates a search process for searching for a communication device as a communication partner.

  Reference numeral 203 denotes a GO Negotiation control unit. Control based on the Wi-Fi Direct protocol specification is performed, and a role in the wireless layer such as which becomes a wireless LAN access point and which becomes a wireless LAN station between communication apparatuses is determined. In Wi-Fi Direct, a communication device that performs a wireless LAN access point function is referred to as a P2P group owner (hereinafter referred to as GO), and a communication device that performs a wireless LAN station function is referred to as a P2P client (hereinafter referred to as CL). When it becomes a GO or wireless LAN access point, a wireless LAN access point function control unit 211 described later is activated, and when it becomes a CL or wireless LAN station, a wireless LAN station function control unit 210 described later is activated. The GO Negotiation protocol is determined by the Wi-Fi Direct specification. Since it is not the point of this invention, description is omitted. In Wi-Fi Direct, a network constructed by GO is referred to as a P2P group. In this embodiment, the network may be described as a P2P group. In the present embodiment, these are described with the same meaning.

  In this specification, a P2P group owner (GO), a P2P client (CL), and a communication device group whose role has not been determined are collectively referred to as a P2P device.

  Reference numeral 204 denotes a DHCP client control unit which is activated when the role of the own communication device becomes a wireless LAN station in the GO Negotiation control unit 203. Reference numeral 205 denotes a DHCP server control unit, which is activated when the role of the own communication device becomes a wireless LAN access point in the GO Negotiation control unit 203.

  A WPS enrollee control unit 206 receives communication parameters necessary for wireless LAN communication from other WPS registrar devices. Similar to the DHCP client control unit 204, it operates when the role of its own communication device is a wireless LAN station. A WPS registrar control unit 207 provides communication parameters necessary for wireless LAN communication to other WPS enrollee devices. Similar to the DHCP server control unit 205, it operates when the role of its own communication device is a wireless LAN access point. The communication parameters provided by the WPS registrar are parameters such as an SSID as a network identifier, an encryption key, an encryption method, an authentication key, and an authentication method.

  A wireless LAN packet receiving unit 208 and a wireless LAN packet transmitting unit 209 handle transmission / reception of all packets including upper layer communication protocols. Reference numeral 210 denotes a wireless LAN station function control unit. It performs authentication / encryption processing when the communication apparatus operates as a wireless LAN station, and participates in a wireless network constructed by an apparatus operating as a wireless LAN access point. A wireless LAN access point function control unit 211 constructs a wireless network when the communication apparatus operates as a wireless LAN access point function, and performs authentication / encryption processing, communication partner apparatus management, and the like. The wireless LAN station function control unit 210 and the wireless LAN access point function control unit 211 can operate either one function or simultaneously.

  A packet routing control unit 212 bridges and routes a communication packet when the wireless LAN access point function control unit 211 is operating. A data storage unit 213 stores and holds software itself, wireless LAN parameters, and various tables such as the aforementioned DHCP address table and ARP table.

  A service discovery control unit 214 is responsible for a service discovery function unique to Wi-Fi Direct. The service discovery function exchanges service information held by the counterpart communication device by transmitting and receiving action frames defined by IEEE 802.11u. Specifically, an SD Query is transmitted, and an SD Response is received as a response. Alternatively, an SD Query from the partner apparatus is received and an SD Response is transmitted as a response.

  A P2P invitation function control unit 215 controls the invitation function defined by the Wi-Fi Direct standard. The invitation function is omitted because it is defined in the Wi-Fi Direct specification, but it is a function that prompts a P2P device for which a GO device or CL device has no determined role as a P2P client.

  A service execution unit 216 executes a service in the application layer. Here, the application layer refers to a service providing layer in an upper layer above the fifth layer in the OSI reference model. That is, the service execution unit 216 executes a print function (print service), an image streaming function (moving image streaming service), a file transfer function (file transfer service), and the like. The file transferred (transmitted / received) by the file transfer service can include data of any format.

  A server unit 217 provides a service in the application layer. The server unit 217 causes the communication device to function as a providing device (server) that provides a service in the application layer. The server unit 217 receives image streaming and receives / stores file data, and operates as a responder. Specifically, for example, it operates as an HTTP (Hypertext Transfer Protocol) server or an FTP (File Transfer Protocol) server.

  A client unit 218 uses a service in the application layer. The client unit 218 causes the communication apparatus to function as a role of a utilization apparatus (client) that uses a service in the application layer. It performs image streaming transmission, file data transmission, etc., and operates as a transmitter. Specifically, for example, it operates as an HTTP client or an FTP client.

  Reference numeral 219 denotes a determination unit. Various determination processes such as determination of consistency between the application layer and the wireless LAN layer and whether or not the service can be continuously executed while maintaining the wireless layer are performed.

  Note that all the functional blocks shown in FIG. 2 are not limited to those provided by software, but may be provided by hardware. Each functional block shown in FIG. 2 has a mutual relationship. Each functional block shown in FIG. 2 is an example, and a plurality of functional blocks may constitute one functional block, or any functional block may be further divided into blocks that perform a plurality of functions. Good.

  FIG. 3 is a configuration diagram of this embodiment.

  It is the figure which showed network A31 (henceforth network A) comprised from communication apparatus A32 (henceforth STA-A) and communication apparatus B33 (henceforth STA-B). Network A is a wireless network formed using Wi-Fi Direct, and is a network constructed by either STA-A or STA-B operating as GO. All the apparatuses shown in FIG. 3 have the configurations shown in FIGS. 1 and 2 described above.

  In this embodiment, STA-A and STA-B use HTTP communication to perform moving image file transmission processing from STA-B to STA-A, and then switch the file transfer direction, and STA -Assume a use case in which transmission processing is performed from A to STA-B. The protocol used in the file transfer service is not limited to HTTP, but can be implemented by other file transfer protocols such as FTP, and this embodiment is not intended to limit the protocol.

  FIG. 4 is a schematic diagram showing an operation sequence between the devices. STA-A and STA-B start service processing by user input processing (F401). In the example of FIG. 4, the service to be started is a file transfer service that transmits a moving image file from STA-B to STA-A. At this time, in STA-A, the start of the file reception service is instructed by a user operation. On the other hand, in STA-B, the start of the file transmission service is instructed by a user operation. In response to the user's instruction, the STA-A searches for a partner apparatus that performs wireless communication (F402). Then, after STA-B is searched, wireless connection with STA-B is performed according to the user instruction (F403). The search process of F402 and the connection process of F403 use a method defined in the Wi-Fi Direct specification described above. Therefore, in these processes, the role of each device in the radio layer between STA-A and STA-B is determined. That is, it is determined which of the STA-A and the STA-B is the Wi-Fi Direct GO and which is the CL.

  At this time, the role of each device in the wireless layer is automatically determined according to the role in the service to be executed. Specifically, the application layer server unit 217 determines a device operating as a service server as a GO in the wireless layer. This is because a device having a server function of a service becomes a GO and operates as a radio base station, so that processing necessary for implementing the service, for example, assignment of addresses in TCP / IP, communication port setting, etc., is reliably performed. Because it can. In the example of FIG. 4, in the file transfer service, the STA-A that performs file reception operates as a server. On the other hand, STA-B that performs file transmission in the file transfer service operates as a client. Therefore, in the example of FIG. 4, STA-A becomes GO.

  Next, a service search is performed between STA-A and STA-B. For example, the search method uses SSDP defined by UPnP (Universal Plug and Play). (F404).

  When the search for the service is completed, the STA-A activates a server (HTTP server in the example of FIG. 4) for executing the service (F405). Then, a port corresponding to the service to be provided is opened, and a process of waiting for connection to the port is performed. When the service search is completed, the STA-B activates a client (HTTP client in the example of FIG. 4) to execute the service (F406).

  Note that the order of server / client activation and service search in each device may be reversed.

  The STA-B connects to the port opened in the STA-A, and transmits a moving image file to the STA-A as a transmitter. Specifically, in the present embodiment, the moving image file is transmitted using HTTP PUT or HTTP POST (F407).

  When the transmission process is completed, STA-A notifies STA-B of the completion of file transfer (F408).

  Consider a case where, after the file transfer from the STA-B to the STA-A is completed, a moving image file is transmitted from the STA-A to the STA-B by a user operation. That is, the role of the device (server or client) in the service to be executed is switched. The service started here is a file transfer service for transmitting a moving image file from STA-A to STA-B. Therefore, contrary to F401, in STA-B, the start of the file reception service is instructed by the user's operation. On the other hand, in STA-A, the start of the file transmission service is instructed by a user operation. In response to these instructions, each apparatus starts service processing (F409, F410).

  Thereafter, the STA-A confirms the connection state of the wireless layer and the content of the service to be executed (F411). This is for determining whether or not the radio layer needs to be reconstructed in order to implement the service. The determination algorithm will be described with reference to a flowchart described later. If the STA-A can execute the service while maintaining the wireless layer connection, the STA-A changes only the roles of the server and the client in the service at the application layer without changing the wireless layer and the communication port. The reason for changing the roles of the server and the client here is that the moving direction of the moving image file is opposite to that of F407, so that the STA-A actively transfers the moving image file to the STA-B as it is the server. This is because they cannot.

  Therefore, the STA-A transmits a service preparation request to the STA-B (F412). Specifically, this request instructs STA-B to start a server that provides a service.

  The STA-B returns a response indicating whether the server can be activated to the STA-A (F413).

  Note that the STA-A may autonomously activate the client without transmitting the service preparation request. STA-B may also autonomously start the server when the server cannot be detected.

  When STA-B can start the HTTP server, STA-A stops its own HTTP server function and starts the HTTP client function (F414). On the other hand, if the STA-B can start the HTTP server, the STA-B stops the HTTP client function and starts the HTTP server function (F415). If the HTTP server function and the HTTP client function can be started simultaneously, it is not always necessary to stop the HTTP client function. When the service connection is completed, the STA-A transmits a moving image file. In the present embodiment, the moving image file is transmitted using HTTP PUT or HTTP POST. (F416). When the transmission process is completed, the STA-B notifies the STA-A of the completion of file transfer (F417).

  As described above, in this embodiment, when there is no wireless layer connection, such as when the first service is executed, control is performed so that the HTTP server becomes GO. And when the wireless layer connection already exists, such as when the service is executed for the second time, even if the role in the application layer is changed, the role in the wireless layer is not changed. Change only the role.

  FIG. 5 is a flowchart showing the operation of the communication apparatus of this embodiment. Each step of this flowchart is processed by the control unit 102 executing a program stored in the storage unit 103. In the following description, a case where a file transfer service is executed as an application layer service performed between communication apparatuses will be described as an example. That is, an example will be described in which a file transfer service is performed between communication apparatuses by one communication apparatus performing a file transmission service and the other communication apparatus executing a file reception service. However, the types of services to which this embodiment can be applied are not limited to file transfer services.

  In step S501, the communication apparatus accepts a service start instruction by a user operation. In the example of FIG. 5, the start of either the file transmission service or the file reception service is instructed by the user.

  In S502, the communication apparatus determines whether the service instructed in S501 can be executed. When the file transmission service is selected, it is determined whether an HTTP client function is provided. When the file reception service is selected, it is determined whether an HTTP server function is provided. If the result of determination in S502 is that service cannot be executed, error processing is performed and processing is terminated (S503). On the other hand, if it is determined in step S502 that the service can be executed, the process proceeds to S504.

  In step S504, the communication apparatus determines whether there is a wireless LAN connection. If it is determined that there is no wireless LAN connection, the communication apparatus determines whether a file transmission service is instructed in S501 or a file reception service is instructed (S505). If it is determined in S505 that the file reception service has been instructed, the communication apparatus determines to be GO as the role of the wireless layer (S510). This is because when the apparatus having the server function of the service becomes a wireless base station, processing necessary for implementing the service, such as address assignment and communication port setting, can be reliably performed. In S511, the communication apparatus searches for a service that can be executed with the communication apparatus that is the communication partner. In this example, it is searched whether or not the communication device as the communication partner can execute the file transmission service. As a search method, for example, the search is performed using SSDP defined by UPnP (Universal Plug and Play). When a desired service can be executed with a communication device as a communication partner, a server is started to execute the service (S512). In this example, the HTTP server is activated. Then, the port of the HTTP server is opened, a connection from the HTTP client is awaited, and a service connection is made with the HTTP client. At this time, the communication apparatus executes a service as a responder (S513). Note that the service search in S511 may be performed after the server is started.

  If it is determined in S505 that the file transmission service has been instructed, the communication apparatus determines that the role of the wireless layer is CL (S506). Thereafter, in S507, the communication device searches for a service that can be executed with the communication device that is the communication partner. In this example, it is searched whether or not the communication device as the communication partner can execute the file reception service. As a search method, for example, the search is performed using SSDP defined by UPnP (Universal Plug and Play). (S507). If a desired service can be executed with the communication device as the communication partner, the client is started to execute the service (S508). In this example, an HTTP client is activated. And it connects to the port opened in the HTTP server, and makes a service connection with the HTTP server. At this time, the communication apparatus executes a service as a transmitter (S509). Note that the service search in S507 may be performed after starting the client.

  If it is determined in S504 that a wireless LAN connection exists, the process proceeds to S514. In this case, as described in F411 of FIG. 4, there may be a case where the execution of the second service process is instructed after the wireless connection has already been completed and the service process has been completed. That is, it is conceivable that the server or client in the application layer service is running.

  In S514, the communication apparatus determines whether the server in the application layer service is running (S514).

  If the server is active, the process advances to step S515, and the communication apparatus determines whether a file transmission service is instructed in step S501 or a file reception service is instructed. If it is determined that the file transmission service has been instructed, the process proceeds to S516. In order to execute the file transmission service, the communication device needs to switch the role from the currently activated HTTP server to the HTTP client. In this embodiment, when the role of the application layer is switched, if the wireless layer connection already exists, only the role of the application layer is switched without reconnecting the wireless layer. That is, only the roles of the server and the client are exchanged without changing the wireless network and IP address settings. Therefore, in S516, the communication apparatus transmits a service preparation request to the communication apparatus that is the communication partner. The service preparation request is a request for starting the HTTP server. Note that the server device may autonomously start the client without transmitting the service preparation request.

  In S517, it is determined whether or not the communication device that is the communication partner can start the server function, and if it is operable, the HTTP client is started (S518). At this time, the communication apparatus executes a service as a transmitter (S519). In S517, if it is determined that the communication device as the communication partner cannot start the server function, error processing is performed and the processing is stopped (S523).

  If it is determined in S515 that the file reception service has been instructed, the communication apparatus needs to start the HTTP server, but the server is already running. Therefore, the process proceeds to S525 without performing any role change processing, and the service is executed.

  If it is determined in S514 that the server is not active, that is, if it is determined that the client is active, the process proceeds to S520. In S520, the communication apparatus determines whether a file transmission service is instructed in S501 or a file reception service is instructed. If it is determined that the file reception service has been instructed, the process proceeds to S521. In order to execute the file reception service, the communication apparatus needs to switch the role from the currently activated HTTP client to the HTTP server. As described above, in this embodiment, when the role of the application layer is switched, when the connection of the wireless layer already exists, only the role of the application layer is switched without reconnecting the wireless layer. To. Therefore, in S521, the communication apparatus waits for reception of a service preparation request sent from the communication apparatus serving as a communication partner. The service preparation request is a request for starting the HTTP server.

  When receiving the service preparation request, the communication apparatus determines whether the HTTP server can be activated in the own apparatus (S522). If the activation is impossible, the process proceeds to S523, an error process is performed, and the process is stopped. If it is determined that the HTTP server can be activated, the process proceeds to S524. In S524, the communication device activates the HTTP server. Then, the communication apparatus executes the service as a service responder (S525).

  If it is determined in S520 that the file transmission service has been instructed, the communication apparatus needs to activate the HTTP client, but the client is already active. Therefore, the process proceeds to S519 without performing the role changing process, and the service is executed.

  Although omitted in this flowchart, it is possible to stop the processing at any step by the user's intention.

  As described above, in this embodiment, when there is no wireless layer connection, such as when the first service is executed, the HTTP server is controlled to be GO. Thus, since the role in the wireless layer is determined according to the role of the application layer, the role in each layer can be controlled efficiently. In particular, since a server (for example, an HTTP server) in the application layer operates as a GO in the wireless layer, a role suitable for management of the TCP / IP network can be set.

  In addition, when a wireless layer connection already exists, such as when the service is executed for the second time, even if the role in the application layer is changed, the role in the wireless layer is not changed. Change only the role. As a result, it is possible to efficiently control the roles in each layer without unnecessarily increasing the processing load.

  Although not described in the flowchart of FIG. 5, the wireless network may be reconfigured when the wireless layer needs to be reset when the communication apparatus operates as a client. In particular, when the third communication device newly joins the network, the network needs to be reconstructed. In that case, the network is once disconnected and the flowchart shown in FIG. 5 is executed again.

[Other Examples]
The above embodiment shows an example for carrying out the present invention, and various modifications can be made without departing from the gist of the present invention.

  The communication device of the above embodiment is not limited to a digital camera, a printer, or the like. It may be a PC or a tablet terminal, and may be a mobile terminal such as a mobile phone or a smartphone. Further, it may be an image processing apparatus such as a copying machine, a scanner, a FAX, or a multifunction machine, or a digital home appliance such as a television or a recorder.

  The above embodiment has been described by taking an example of a wireless LAN compliant with IEEE 802.11. However, the present invention may be implemented in other wireless communications such as wireless USB, MBOA, Bluetooth (registered trademark), UWB, and ZigBee (registered trademark). Moreover, you may implement in wired communication media, such as wired LAN. Here, MBOA is an abbreviation for Multi Band OFDM Alliance. UWB includes wireless USB, wireless 1394, WINET, and the like.

  Furthermore, the present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program code. It is a process to be executed. In this case, the program and the storage medium storing the program constitute the present invention.

31 Network A
32 STA-A (Wi-Fi Direct GO)
33 STA-B (CL for Wi-Fi Direct)

Claims (12)

A communication device,
Construction means that operates as a base station to construct a network;
Participation means that operates as a terminal and joins the network;
Determining means for determining whether to operate as the base station or the terminal;
Operating as a client of a service executed with another communication device, and transmitting means for transmitting the file to the other communication device;
Receiving means for operating as a server for services executed with other communication devices and receiving files transmitted from the other communication devices;
Have
The said determination means determines to operate | move as said base station, when operate | moving as a server of the service performed between said other communication apparatuses.   The communication apparatus according to claim 1, wherein transmission and reception of the file are performed using HTTP, the server is an HTTP server, and the client is an HTTP client.   The communication apparatus according to claim 1, wherein the service executed with the other communication apparatus is a file transfer service. Having a reception means for receiving a file reception instruction or a file transmission instruction by the user;
4. The apparatus according to claim 1, wherein the server operates as the server when an instruction to receive a file is received by the reception unit, and operates as the client when an instruction to transmit a file is received by the reception unit. The communication apparatus as described in any one. A communication device,
Construction means that operates as a base station to construct a network;
Participation means that operates as a terminal and joins the network;
A communication means that operates in the role of either the base station or the terminal and communicates with another communication device;
Determining means for determining a role of the communication device for executing a service in an application layer;
A changing means for changing a role determined by the determining means after executing a service in an application layer according to the role determined by the determining means and maintaining a role for communication by the communication means;
A communication apparatus comprising:   The communication apparatus according to claim 5, wherein the role determined by the determination unit is a server or a client for executing a service in an application layer.   When the role of the communication device determined by the determination unit is a server, the changing unit changes to a client, and when the role of the communication device determined by the determination unit is a client 7. The communication apparatus according to claim 6, wherein the communication apparatus is changed to a server.   The communication apparatus according to claim 5, wherein the service in the application layer is a file transfer service.   The communication apparatus according to any one of claims 1 to 3, wherein the base station and the terminal are a base station and a terminal in a wireless LAN compliant with IEEE 802.11. A communication device control method comprising:
A construction process that operates as a base station to construct a network;
A participation process that operates as a terminal and joins the network;
A determination step of determining whether to operate as the base station or the terminal;
A transmission step of operating as a client of a service executed with another communication device and transmitting a file to the other communication device;
A reception step of receiving a file transmitted from the other communication device, operating as a server of a service executed with the other communication device;
Have
The method for controlling a communication apparatus, wherein the determining step determines that the base station operates when operating as a server for a service executed with the other communication apparatus. A communication device control method comprising:
A construction process that operates as a base station to construct a network;
A participation process that operates as a terminal and joins the network;
A communication step of operating in the role of either the base station or the terminal and communicating with another communication device;
A determining step of determining a role of the communication device for executing a service in an application layer;
After executing the service in the application layer according to the role determined by the determination step, the change step of changing the role determined by the determination step while maintaining the role for communication by the communication step;
A method for controlling a communication apparatus, comprising:   The program for operating a computer as a communication apparatus as described in any one of Claims 1 thru | or 9.

Images